Integrated circuits (ICs) are typically produced by forming a plurality of ICs on a semiconductor substrate, such as silicon. The ICs include one or more layers formed on the substrate (e.g., semiconductor layers, insulation layers, and metallization layers). The individual ICs are separated by lanes. The finished ICs on the wafer are then separated into individual ICs by, for instance, sawing the wafer along the lanes. Separation of the wafer into individual ICs may be referred to as dicing. Sawing may be performed using various mechanical cutting and laser cutting methods. Mechanical cutting tools tend to cause chipping of the back-side or front-side of a substrate. Laser cutting tends to cut unevenly in metallization layers covering entirely or partly the saw lanes of the substrate.
During a stealth laser dicing process, the laser focuses into the material and melts the mono-crystalline silicon. The material re-crystallizes as polycrystalline silicon, which induces stress into the material due to higher volume of the poly-crystalline structure. This stress creates a crack, which is used for die separation.
For one particular type of product, a radio frequency identification device (RFID) tags, the feature for the die separation, has become a challenge during the later RFID tag production process. Once the device die is embedded in a glue within the RFID tag, bending forces may be transferred from the die side into the laser modification zone (on the sidewalls of the embedded die) resulting in cracking at die edges.
There exists a need for to eliminate this shortcoming in the assembly of RFID devices.